2KrakatoaKrakatoa exploded August 27, 1883 obliterated 5 square miles leaving a crater 3.5 miles across and meters deep.33 ft high tsunami waves hit Anjer and Merak demolishing the towns and killing most of the people> 10,000. In Merak wave rose to 135 ft ASL and moved 100 ton Coral blocks up on the shore.
3Krakatoa TsunamiTsunami swept over 300 coastal towns and villages. Over 40,000 were killed by the tsunami waves.Sea withdrew at Bombay, India and killed one person in Sri Lanka.Tsunami produced by explosion and associated shock wave and pyroclastic flows.
9Jakarta Tide Gauge Barograph Record shows early arrival of the atmos pressure waves
10Tide Gauge Records from Atmospheric Pressure Waves
11HYDROVOLCANIC EXPLOSIONS Generated by Interaction of Magma with ground water.Called Surtseyan after 1963 eruption off Iceland.Water flashes to steam and expands explosivelyH2O(LIQUID) > H2O(GAS) at constant volume has a 30 Kbar PRESSURE
12Modeling Hydrovolcanic Explosions Water described as an Explosive and a propagating detonation is modeled for hot liquid water going to gas.BKW steady state conditions of C-J state of 89 kbar, 5900 m/sec, 0.75 cc/gm, 1100o K for liquid water with kcal/mole Heat of Formation to model energy (19 kcal/mole) for hot lava heating water to ~1100o K.
13Krakatoa Model Spherical Geometry 2Km-3200 m100 m Water500 m Hot SpotKmAXISBASALT
20TSUNAMI WAVE Radius Wave Height Period 4 km 130 meters 25 sec Inside the hydrovolcanic explosion at1.5 km radius it expands up for morethan 2 km with initial pressure >25 kb
21Did it look like 1946 Bikini Shot? 21 Kt at 27 m depth – Krakatoa megatons
22KrakatoaThe tsunamis had periods of less than 5 minutes and wavelength of less than 7 km thus rapidly decayed.The far field effects were negligible but recorded on tide gauges around the world. Caused by air shock propagating and coupling to the ocean.